This invention relates generally to duplicating machines and, more particularly, to ink fountain assemblies for use in duplicating machines. Specifically, the invention relates to a preparation station for ink fountains and the use of a preparation station in a system utilizing interchangeable ink fountains.
Printing machines, such as rotary offset lithographic duplicating machines, normally include a printing couple which comprises a number of cylinders and/or rollers such as impression cylinders, master cylinders, blanket cylinders, ductor rollers, regulator rollers, and the like. An ink fountain is disposed at the rear end of the machine for feeding ink to the various rollers of the printing couple which transfers images to copy sheets.
Conventional ink fountain assemblies normally take the form of a fountain trough defined by an elongated blade extending along one side and an ink fountain roller extending along the opposite side of the trough. The ink fountain roller transfers the ink to the other rollers of the printing couple. The blade is adjustable by a plurality of thumb screws to vary the gap between an edge of the blade and the ink fountain roller. In some instances, the gap is maintained of generally equal dimensions along its length to maintain consistency in the amount of ink applied to the roller uniformly along the length of the roller. However, in many instances the width of the gap varies along its length depending upon the amount of ink necessary to duplicate a given master having varying densities of a particular ink color.
One of the major problems encountered in printing or duplicating systems described above is the down time required to change types of inks. In the printing industry it is a common practice to change colors of ink, such as in a four-color offset lithographic duplicating machine. The type of ink, such as rubber base ink, oil base ink or electrostatic ink also is changed, as with fast drying inks for hard surface paper stock or slower drying inks for general paper stock. This problem is becoming increasingly prevalent due to the industry shifting from a high percentage of black ink printing to higher quality work of various colors and color processes.
High hourly labor rates require that strong consideration be given to reducing press down time in changing ink colors or types. Each time the ink is changed for a given run of stock, not only does the ink in the fountain have to be changed and the fountain itself cleaned for a subsequent ink color or type, but the rollers of the printing couple also must be cleaned with a solvent. However, cleaning the printing couple rollers takes considerably less time than changing the ink in the fountain and cleaning the fountain. In fact, the printing couple rollers can be cleaned during continuous running in a basic time of approximately 70 seconds. It would be desirable to be able to simply bodily remove the previous ink fountain during this short clean-up time and replace the entire fountain with one that already has been cleaned and fully prepared with a new type or color of ink.
This invention is directed to providing a novel ink preparation station for ink fountains in a system which permits complete interchangeability of ink fountains between the duplicating machine and the preparation station. In this manner, a subsequent ink fountain assembly can be completely prepared with a different color or type of ink, including adjusting the ink flow through gap, so that the fountain is ready for immediate interchangement onto the duplicating machine when the previous run is completed.